The invention pertains to a marking gun for printing and applying adhesive labels with pricing and the like and more particularly to a hand-held merchandise marking gun.
Mass marketing of retail goods requires the repetitious marking of individual items with price or other information. Marks may either be directly stamped on the goods or first imprinted on adhesive label and the label affixed to the goods. In order to conveniently apply and print such labels, merchandise marking guns have been developed which carry a supply of adhesive labels on a backing tape and a printing head with a variety of selectable characters which may be impressed on the labels. Typically, in such marking guns, as for example described in U.S. Pat. No. 3,800,701, the labels are separated from the backing tape by passing the backing tape around a sharp radius of curvature. The labels have been printed by a printing head within the gun prior to separation from the backing tape.
A primary problem in constructing a label marker of this type is in accurately advancing the labels to the printing position. Some devices employ friction drive rollers to advance the labels. However, when the rollers pull on the silicon coated backing tape of the adhesive labels, silicon eventually coats the rubber rollers and the rollers cease to operate properly. In other marking devices, shuttle mechanisms are used to advance the labels but the complexity of these mechanisms often leads to high cost, inefficiency, and unreliability.
In the marking gun of the type described in U.S. Pat. No. 3,900,701, a drive wheel having projecting teeth is used to advance the label tape by engaging the teeth in perforations in the tape backing so that positive indexing is thereby achieved. A disadvantage of the mechanism is that the tape must be placed in registration with the teeth of the drive wheel when the tape supply is loaded into the marking gun. Any misregistration can cause jamming of the tape that is in the gun or misregistration in the printing on the labels.
Another problem in label marking guns is in controlling the printing force so that a relatively consistent printing pressure is applied to each label. Since the printing heads are directly coupled to the trigger in many prior art guns, the operator must rely on his subjective judgment as to whether or not he is exerting a constant printing pressure from one label to the next.
Still another problem of merchandise marking guns is that a certain amount of force is required to press the printed label against the merchandise to be marked. This can be done with a roller, however, the roller surface can cause the freshly printed label to be smeared. A further problem is that the application roller must absorb the impact without breaking as the label is pressed onto the goods. Also, in some prior art merchandise marking guns, the ink roller for inking the printing head is difficult to either re-ink or to replace.